Face seals are utilized to seal components having opposed surfaces wherein the seal is sandwiched between the opposed surfaces or "faces" and sealing occurs at the lateral portions of the annular seal body and the sealing forces are axial with respect to the body configuration.
In installations utilizing face seals the components being coupled employ coupling or attachment elements for maintaining the coupled components in a face-to-face relationship, and if elastomer swelling has caused the axial dimension of the face seal to increase, the coupling components cannot be interengaged, or if swelling has occurred after the coupling has been interconnected, uncoupling of the components becomes very difficult. Seal swelling occurs with certain types of fluids, such as aircraft fuels, and few seal compositions are impervious to swelling.
If the dimensions of a face seal are minimized in the axial direction to reduce swelling problems shrinkage of the seal, or tolerance variations in the coupling components, will prevent a fluid-tight seal from occurring. Accordingly, it will be appreciated that serious problems occur with face seals due to changes in axial dimension resulting from swelling or from shrinkage.
It is an object of the invention to produce a face seal which compensates for elastomer swell, and does not require additional components to accommodate dimensional changes.
An additional object of the invention is to provide an elastomer face seal which is self-energized in that only the seal material itself maintains the seal lateral portions in sealing engagement with the faces to be contacted, and no metal or elastic internal rings are needed for seal energization.
Yet another object of the invention is to provide an elastomeric face seal having voids so located as to accommodate the seal material during swelling without adversely affecting the operational characteristics, and wherein the need for energizing components is eliminated.
In the practice of the invention the annular face seal consists of an elastomeric annular body having a base portion from which lateral portions extend in a common radial direction. A plurality of bridges are homogeneously defined of the seal material and extend between the lateral portions for reinforcing and locating the lateral portions. The bridge segments are circumferentially spaced to provide clearances therebetween for accommodating the seal body material during swelling, and the bridges energize the seal to produce the desired resistance to axial forces necessary to achieve the required operation.